Turbine bucket with notched squealer tip
A turbine bucket having an airfoil is disclosed. The airfoil may include a pressure side and a suction side extending between a leading edge and a trailing edge. In addition, the airfoil may include a tip. The tip may include a tip floor and a tip wall extending outwardly from the tip floor. The tip wall may include an inner surface defining an inner perimeter of the tip wall. Moreover, a plurality of notches may be defined by the inner surface around at least a portion of the inner perimeter.
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The present subject matter relates generally to turbine buckets and, more particular, to a notched squealer tip for a turbine bucket.
BACKGROUND OF THE INVENTIONIn an air-ingesting turbo machine (e.g., a gas turbine), air is pressurized by a compressor and then mixed with fuel and ignited within an annular array of combustors to generate hot gases of combustion. The hot gases flow from each combustor through a transition piece for flow along an annular hot gas path. Turbine stages are typically disposed along the hot gas path such that the hot gases flow through first-stage nozzles and buckets and through the nozzles and buckets of follow-on turbine stages. The turbine buckets may be secured to a plurality of rotor disks comprising the turbine rotor, with each rotor disk being mounted to the rotor shaft for rotation therewith.
A turbine bucket generally includes an airfoil extending radially outwardly from a substantially planar platform and a shank portion extending radially inwardly from the platform for securing the bucket to one of the rotor disks. The tip of the airfoil is typically spaced radially inwardly from a stationary shroud of the turbo machine such that a small gap is defined between the tip and the shroud. This gap is typically sized as small as practical to minimize the flow of hot gases between the airfoil tip and the shroud.
In many instances, the tip of the airfoil may include a squealer tip wall extending around the perimeter of the airfoil so as to define a tip cavity and a tip floor therebetween. The squealer tip wall is generally used to reduce the size of the gap defined between the airfoil tip and the shroud. However, this creates an additional component of the turbine bucket that is subject to heating by the hot gas flowing around the airfoil. Thus, cooling holes are typically defined in the tip floor to allow a cooling medium to be directed from an airfoil cooling circuit within the airfoil to the tip cavity.
Accordingly, an improved tip configuration that allows for enhanced cooling of an airfoil tip would be welcomed in the technology.
BRIEF DESCRIPTION OF THE INVENTIONAspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one aspect, the present subject matter is directed to a turbine bucket including an airfoil. The airfoil may include a pressure side and a suction side extending between a leading edge and a trailing edge. In addition, the airfoil may include a tip. The tip may include a tip floor and a tip wall extending outwardly from the tip floor. The tip wall may include an inner surface defining an inner perimeter of the tip wall. Moreover, a plurality of notches may be defined by the inner surface around at least a portion of the inner perimeter.
In another aspect, the present subject matter is directed to a turbine bucket including an airfoil. The airfoil may include a pressure side and a suction side extending between a leading edge and a trailing edge. In addition, the airfoil may include a tip. The tip may include a tip floor and a tip wall extending outwardly from the tip floor. The tip wall may include an offset portion that is recessed relative to at least one of the pressure side or the suction side such that a tip shelf is defined at the offset portion. Moreover, a plurality of notches may be defined by the outer surface of the offset portion.
In a further aspect, the present subject matter is directed to a squealer tip for an airfoil. The squealer tip may include a tip floor and a tip wall extending outwardly from the tip floor along a pressure side and a suction side of the airfoil. The tip wall may include an inner surface defining an inner perimeter of the tip wall. In addition, a plurality of notches may be defined by the inner surface around at least a portion of the inner perimeter.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
In general, the present subject matter is directed to a turbine bucket having an improved squealer tip. Specifically, in several embodiments, the squealer tip may include a tip floor and a notched tip wall extending outwardly from the tip floor. For instance, in one embodiment, the inner surface of the tip wall may define a plurality of notches around the inner perimeter of the tip wall. Additionally, a plurality of cooling holes may be defined in the tip floor for supplying a cooling medium (e.g., air, water, steam) to the squealer tip. For example, the cooling holes may be defined in the tip floor so as to be aligned with the notches, such as by being positioned within the notches.
In alternative embodiments, the outer surface of the tip wall may define a plurality of notches. For instance, in several embodiments, a portion of the tip wall may be recessed such that a tip shelf is formed along the pressure side and/or suction side of the squealer tip. In such embodiments, the notches may be defined around the outer perimeter of the recessed portion of the tip wall. Additionally, a plurality of cooling holes may be defined in the tip shelf for supplying a cooling medium to the squealer tip.
It should be appreciated that numerous advantages may be provided by the disclosed notched tip wall. For example, the notches may provide an increased surface area for cooling the tip wall. In addition, the notches may also provide a means for forming angled cooling holes within the tip floor and/or the tip shelf. For instance, as will be described below, the notches may be angled relative to the tip floor and/or the tip shelf. As such, angled cooling holes may be formed within the notches without the need to use custom tooling and/or specialized manufacturing processes. Such angled cooling holes may allow for cooling medium to be diverted directly against the inner and/or outer surface of the tip wall, thereby providing enhanced cooling for the tip wall.
Referring now to the drawings,
During operation of the turbo machine 10, the compressor section 12 pressurizes air entering the machine 10 through the inlet section 11 and supplies the pressurized air to the combustors of the combustor section 14. The pressurized air is mixed with fuel and burned within each combustor to produce hot gases of combustion. The hot gases of combustion flow in a hot gas path from the combustor section 14 to the turbine section 16, wherein energy is extracted from the hot gases by the turbine buckets 24. The energy extracted by the turbine buckets 24 is used to rotate the rotor disks 22 which may, in turn, rotate the shaft 18. The mechanical rotational energy may then be used to power the compressor section 12 and generate electricity. The hot gases exiting the turbine section 16 may then be exhausted from the machine 10 via the exhaust section 17.
Referring now to
As shown, the turbine bucket 24 generally includes a shank portion 26 and an airfoil 28 extending from a substantially planar platform 30. The platform 30 generally serves as the radially inward boundary for the hot gases of combustion flowing through the turbine section 16 of the turbo machine 10 (
The airfoil 28 may generally extend radially outwardly from the platform 30 and may include an airfoil base 32 disposed at the platform 30 and an airfoil tip 34 disposed opposite the airfoil base 32. As such, the airfoil tip 34 may generally define the radially outermost portion of the turbine bucket 24 and, thus, may be configured to be positioned adjacent to a stationary shroud 36 (shown in dashed lines in
Additionally, the turbine bucket 24 may also include an airfoil cooling circuit 46 (shown in dashed lines in
Referring particularly to
It should be appreciated one or more dust holes 60 may also be defined through the tip floor 52 for expelling dust and/or other debris contained within the cooling medium supplied through the airfoil circuit 46. For example, as shown in
The tip wall 50 of the airfoil tip 34 may generally be configured to for an extension of the airfoil 28. For example, as shown in
Additionally, in several embodiments, the tip wall 50 may be notched around at least a portion of its inner perimeter. Specifically, as shown in
In general, the notches 66 may be formed in the tip wall 50 so as to define any suitable shape. For example, as shown in
Additionally, as shown in
Moreover, in several embodiments, the cooling holes 56 defined in the tip floor 52 may be aligned with the notches 66 defined in the tip wall 50. For example, as shown in
In other embodiments, the cooling holes 56 may be defined in the tip floor 52 at any other suitable position relative to the notches 66. For example, the cooling holes 56 may be defined in the tip floor 52 so as to be positioned outside the notches 66 (i.e., at a location outside the area defined between the notch edges 68 the notches 66). Specifically, as shown in
Additionally, in several embodiments, the cooling holes 56 may be oriented perpendicularly or non-perpendicularly within the tip floor 52. Specifically, in one embodiment, the cooling holes 56 may be angled relative to the tip wall 50. For instance, as shown in
It should be appreciated that, by angling the notches 66 as described above, the angled cooling holes 56 shown in
Referring now to
As shown, the tip wall 50 may include an offset portion 82 that is recessed relative to the pressure and/or suction sides 38, 40 of the airfoil 28, thereby forming a tip shelf 80 adjacent to such offset portion 82. For example, as shown in
In several embodiments, when a tip shelf 80 is formed in the airfoil tip 34, the outer perimeter of the tip wall 50 may be notched around the portion of the tip wall 50 defined by the offset portion 82. Specifically, as shown in
Moreover, a plurality of cooling holes 156 may also be defined in the tip shelf 80 for directing a cooling medium (indicated by arrows 58) from the passages 48 of the airfoil cooling circuit 46 to the offset portion 82 of the tip wall 50. For example, as shown in
It should be appreciated that, in additional embodiments of the present subject matter, the disclosed notches 66, 166 may be formed around portions of both the inner and outer perimeters of the tip wall 50. For example, in the embodiment shown in
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims
1. A turbine bucket comprising:
- an airfoil including a pressure side and a suction side extending between a leading edge and a trailing edge, the airfoil further including a tip, the tip comprising: a tip floor; and a tip wall extending outwardly from the tip floor, the tip wall including an offset portion that is recessed relative to at least one of the pressure side or the suction side such that a tip shelf is defined at the offset portion, the offset portion of the tip wall defining an outer surface, wherein a plurality of notches are defined by the outer surface of the offset portion of the tip wall, each of the plurality of notches being defined between opposed notch edges of the outer surface and extending radially between the tip shelf and a top surface of the tip wall, wherein a plurality of cooling holes are defined in the tip shelf, a first cooling hole of the plurality of cooling holes being aligned with a first notch of the plurality of notches, the first cooling hole defining an outlet at the tip shelf for directing a cooling medium from an internal cooling circuit of the airfoil to an exterior of the airfoil, wherein the first cooling hole extends lengthwise between the internal cooling circuit and the tip shelf such that the first cooling hole is angled towards the outer surface of the offset portion of the tip wall.
2. The turbine bucket of claim 1, wherein the offset portion of the tip wall is disposed on the pressure side of the airfoil.
3. The turbine bucket of claim 1, wherein each of the plurality of notches extends at an angle along the outer surface of the offset portion of the tip wall between the tip floor and the top surface of the tip wall.
4. The turbine bucket of claim 3, wherein the angle ranges from 1 degree to 30 degrees.
5. The turbine bucket of claim 3, wherein the outer surface of the offset portion of the tip wall and the first cooling hole are angled in the same direction.
6. The turbine bucket of claim 1, wherein at least one cooling hole of the plurality of cooling holes is defined in the tip shelf so as to be positioned between two notches of the plurality of notches.
7. The turbine bucket of claim 1, wherein the outlet of the first cooling hole defines a dimensional parameter that is smaller than an area defined between the opposed notch edges of the first notch.
8. The turbine bucket of claim 7, wherein the outlet of the first cooling hole is spaced apart from the first notch along the tip shelf such that portions of the tip shelf extend outwardly from the outlet around an entire perimeter of the outlet.
9. The turbine bucket of claim 7, wherein the dimensional parameter corresponds to a cross-sectional area of the outlet at the tip shelf.
10. The turbine bucket of claim 7, wherein the outlet of the first cooling hole is positioned entirely within the area defined between the opposed notch edges of the first notch.
11. The turbine bucket of claim 10, wherein the area is defined between the opposed notch edges at a radial location at which the first notch intersects the top surface of the tip wall.
12. The turbine bucket of claim 7, wherein the outlet of the first cooling hole is positioned entirely outside the area defined between the opposed notch edges of the first notch.
13. A squealer tip for an airfoil, the squealer tip comprising:
- a tip floor; and
- a tip wall extending outwardly from the tip floor, the tip wall including an offset portion that is recessed relative to at least one of the pressure side or the suction side such that a tip shelf is defined at the offset portion, the offset portion of the tip wall defining an outer surface,
- wherein a plurality of notches are defined by the outer surface of the offset portion of the tip wall, each of the plurality of notches being defined between opposed notch edges of the outer surface and extending radially between the tip shelf and a top surface of the tip wall,
- wherein a plurality of cooling holes are defined in the tip shelf, a first cooling hole of the plurality of cooling holes being aligned with a first notch of the plurality of notches, the first cooling hole defining an outlet at the tip shelf for directing a cooling medium from an internal cooling circuit of the airfoil to an exterior of the airfoil,
- wherein the first cooling hole extends lengthwise between the internal cooling circuit and the tip shelf such that the first cooling hole is angled towards the outer surface of the offset portion of the tip wall.
14. The squealer tip of claim 13, wherein each of the plurality of notches extends at an angle along the outer surface of the offset portion of the tip wall between the tip floor and the top surface of the tip wall.
15. The squealer tip of claim 14, wherein the angle ranges from 1 degree to 30 degrees.
16. The squealer tip of claim 14, wherein the outer surface of the outer portion of the tip wall and the first cooling hole are angled in the same direction.
17. The squealer tip of claim 13, wherein the outlet of the first cooling hole defines a dimensional parameter that is smaller than an area defined between the opposed notch edges of the first notch.
18. The squealer tip of claim 17, wherein the outlet of the first cooling hole is spaced apart from the first notch along the tip shelf such that portions of the tip shelf extend outwardly from the outlet around an entire perimeter of the outlet.
19. The squealer tip of claim 13, wherein the outlet of the first cooling hole is positioned entirely within or entirely outside the area defined between the opposed notch edges of the first notch.
20. The squealer tip of claim 19, wherein the outlet of the first cooling hole is positioned entirely within the area defined between the opposed notch edges of the first notch, the area being defined between the opposed notch edges at a radial location at which the first notch intersects the top surface of the tip wall.
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Type: Grant
Filed: Jul 26, 2012
Date of Patent: Oct 18, 2016
Patent Publication Number: 20140030102
Assignee: General Electric Company (Schenectady, NY)
Inventors: Niraj Kumar Mishra (Bangalore), Xiuzhang James Zhang (Simpsonville, SC), Murugesan Seerangan (Bangalore), Sachin Kumar Rai (Ranchi)
Primary Examiner: Craig Kim
Assistant Examiner: Alexander White
Application Number: 13/558,685
International Classification: F04D 29/38 (20060101); F01D 5/20 (20060101);